Death by pullups
With a continuously running clock do one pull­up the first minute, 2 pullups the second minute, 3 pullups the third minute… continuing as long as you are able. Use as many sets each minute as needed.

Tabata Something Else
Complete 32 intervals of 20 seconds of work followed by 10 seconds of rest where
the first 8 intervals are pullups, the second 8 are pushups, the third 8 intervals
are situps, and finally, the last 8 intervals are squats. There is no rest between
exercises.

With a continuously running clock do one Handstand pushup the first minute, 2 pullups the second minute, 3 handstand pushups the third minute and 4 pullups the 4th minute continuing in this pattern as long as you are able. If your pace falls behind the count, continue to alternate exercises while recording reps for a total of twenty minutes.

handstand pushups 5×5
Maximize range of motion by using blocks or chairs.